This invention relates to molten metal pouring tubes, and more particularly to such tubes that are specially adapted for the pouring of molten steel.
As is known to those skilled in the art, molten metal pouring tubes are an important part of the equipment used to fill metal moulds from the bottom. From a molten metal laden receptacle (such as a ladle), usually located beneath the mould, the molten metal passes through a pouring tube essentially vertically to the underside of the selected mould. Application of pressure to the surface of the molten metal forces metal upwardly through the pouring tube and thence through a gated mating aperture in the base of the mould into the interior thereof. Accordingly, by regulating the pressure of the air or other gaseous substance onto the surface of the molten metal, the flow of such metal upwardly into a mould can be controlled.
The bottom introduction of molten metal into certain special moulds has found substantial commercial favor, particularly in the field of direct steel slab casting. However, although such bottom entry molten metal casting provides a number of advantages, the harsh environment of extraordinary high temperatures has resulted in limited tube life. Moreover, heretofore known tubes that are capable of withstanding molten steel temperatures and the pressures of vertical columns of significant height have been expensive and relatively shortly lived; and consequently there has been a continuing need for molten metal pouring tubes with substantially improved operational life.